1. Field Of The Invention
This invention relates to an impact receiving structure for a platen or a type drum of an impact type printing mechanism.
2. Description Of The Prior Art
There has been heretofore proposed a belt type impact printer in which types are disposed on a belt. A type belt is driven by pulleys to run at the front of a platen which also serves as a belt guide. The platen is screwed at attachment portions to a base. The types on the type belt, which travels at the front of the platen, are printed on a recording paper when printing hammers are driven by printing magnets to strike the types through the recording paper and an ink ribbon. In an ordinary operation of belt type printers of this kind, the contents of input data are arranged on a line of digits by electronic circuit processing, and at each time when the type corresponding to the data of each digit passes at the front position of a printing hammer, a magnet driver is driven to actuate the corresponding hammer with the top end of the magnet driver, thereby printing to record the input data. Springs are employed for pulling the hammers back to their restored positions. When driven for printing, to the hammer is imparted an impulsive force of several kg/cm or a few dozen kg/cm, so that the striking energy is mostly applied to the platen through the ink ribbon, the recording paper and the type belt and is further transmitted to the entire printing mechanism through the base to which the platen structure is secured at the attachment portions, thus causing noises. If there are data to be printed for all digits, the hammers are driven all together usually within several hundred milli-seconds, generating very disturbing noises. In attempts to reduce noise, it is the practice in the art to attach a polyurethane sound absorbing material to the inside of the printer cover or to cover the entire printer with a sound shield, as required. With such means, however, the noise generated by the printing mechanism cannot be sufficiently abated.